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authorPankaj Dubey <pankaj.dubey@samsung.com>2014-09-24 16:25:54 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-07 10:52:19 -0800
commit41fb96a4b619afd2272acb6e981a7581efa8e118 (patch)
tree3fdfb242ce3c25e8a3ed49c88e5b823a7c005398
parent1f648f88cea7f9b16ea8964cd81b92fb08df75a5 (diff)
downloadlinux-linaro-stable-41fb96a4b619afd2272acb6e981a7581efa8e118.tar.gz
kobject: fix NULL pointer derefernce in kobj_child_ns_ops
We will hit NULL pointer dereference if we call platform_device_register_simple or platform_device_add at very early stage. I have observed following crash when called platform_device_add from "init_irq" hook of machine_desc. This patch fixes this issue and let system handle this case gracefully instead of kernel panic. [0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000c [0.000000] pgd = c0004000 [0.000000] [0000000c] *pgd=00000000 [0.000000] Internal error: Oops: 5 [#1] PREEMPT ARM [0.000000] Modules linked in: [0.000000] CPU: 0 PID: 0 Comm: swapper Tainted: G W 3.17.0-rc6-00198-ga1603f1-dirty #319 [0.000000] task: c05b23f0 ti: c05a8000 task.ti: c05a8000 [0.000000] PC is at kobject_namespace+0x18/0x58 [0.000000] LR is at kobject_add_internal+0x90/0x2ec [snip] [0.000000] [<c01b1df0>] (kobject_namespace) from [<c01b2338>] (kobject_add_internal+0x90/0x2ec) [0.000000] [<c01b2338>] (kobject_add_internal) from [<c01b2728>] (kobject_add+0x4c/0x98) [0.000000] [<c01b2728>] (kobject_add) from [<c0226274>] (device_add+0xe8/0x51c) [0.000000] [<c0226274>] (device_add) from [<c0229c70>] (platform_device_add+0xb4/0x214) [0.000000] [<c0229c70>] (platform_device_add) from [<c022a338>] (platform_device_register_full+0xb8/0xdc) [0.000000] [<c022a338>] (platform_device_register_full) from [<c0570214>] (exynos_init_irq+0x90/0x9c) [0.000000] [<c0570214>] (exynos_init_irq) from [<c056c18c>] (init_IRQ+0x2c/0x78) [0.000000] [<c056c18c>] (init_IRQ) from [<c0569a54>] (start_kernel+0x22c/0x378) [0.000000] [<c0569a54>] (start_kernel) from [<40008070>] (0x40008070) [0.000000] Code: e590000c e3500000 0a00000e e5903014 (e593300c) Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--lib/kobject.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/kobject.c b/lib/kobject.c
index 58751bb80a7c..03d4ab349fa7 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -976,7 +976,7 @@ const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
{
const struct kobj_ns_type_operations *ops = NULL;
- if (parent && parent->ktype->child_ns_type)
+ if (parent && parent->ktype && parent->ktype->child_ns_type)
ops = parent->ktype->child_ns_type(parent);
return ops;